Downhole Perforating System

ABSTRACT

Systems and methods for downhole perforation. A method may comprise lowering a downhole perforating system into a casing of a wellbore, wherein the downhole perforating system may comprise 1,1-diamino 2,2-dinitroethylene; detonating the 1,1-diamino 2,2-dinitroethylene; and perforating the casing. A downhole perforating system may comprise a firing head subassembly, a gun subassembly and an explosive component comprising 1,1-diamino 2,2-dinitroethylene.

BACKGROUND

After drilling various sections of a subterranean wellbore that traverses a formation, a casing string may be positioned and cemented within the wellbore. This casing string may increase the integrity of the wellbore and may provide a path for producing fluids from the producing intervals to the surface. To produce fluids into the casing string, perforations may be made through the casing string, the cement and a short distance into the formation.

These perforations may be created by detonating a series of shaped charges that may be disposed within the casing string and may be positioned adjacent to the formation. Specifically, one or more perforating guns may be loaded with shaped charges that may be connected with a detonator via a detonating cord. The perforating guns may then be attached to a tool string that may be lowered into the cased wellbore. Once the perforating guns are properly positioned in the wellbore such that the shaped charges are adjacent to the formation to be perforated, the shaped charges may be detonated, thereby creating the desired perforations.

Conventional explosive components used for oilfield perforating, under certain conditions, such as, during unanticipated accident scenarios, may react and cause unintended outcomes to oil and gas workers and even the general public.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some examples of the present disclosure, and should not be used to limit or define the disclosure.

FIG. 1 is a schematic illustration of an example of a downhole perforating system including diamine-dinitro IHE.

FIG. 2 is a schematic illustration of an example of a downhole perforating system including diamine-dinitro IHE.

FIG. 3 is a schematic illustration of an example of a detonating cord initiator including diamine-dinitro IHE.

FIG. 4 is a schematic illustration of an example of a donor booster and an acceptor booster including diamine-dinitro IHE.

FIG. 5 is a schematic illustration of an example of a shaped charge including diamine-dinitro IHE.

DETAILED DESCRIPTION

This disclosure may generally relate to systems and methods for perforating downhole tubulars, such as, for example casing. This disclosure may relate to systems and methods for using an explosive component comprising 1,1-diamino 2,2-dinitroethylenediamine-dinitro IHE, in oilfield perforation operations. As used herein, 1,1-diamino 2,2-dinitroethylene is referred to as a diamine-dinitro insensitive high explosive or diamine-dinitro IHE. Perforating systems and methods that use diamine-dinitro IHE as an explosive component may enhance safety significantly in all aspects of the lifecycle of perforating activities, such as, for example, loading at the shop; transportation by highway, air, or water; wellsite handling; retrieval after misruns; and downloading.

Diamine-Dinitro IHE may have the chemical formula C₂(NH₂)₂(NO₂)₂. Any of a variety of suitable techniques may be used for synthesis of diamine-dinitro IHE. Without limitation, diamine-dinitro IHE may be synthesized by a process that includes the nitration of a heterocyclic compound followed by hydrolysis to produce diamine-dinitro IHE. Diamine-dinitro IHE may have a molecular weight of approximately 148.08 and a density of approximately 1.86 to 1.89 g/cm³, for example, a density of about 1.885 g cm³ as determined by powder diffraction. Diamine-dinitro IHE may be chemically stable and may have the same oxygen balance as cyclotrimethylenetrinitramine (“RDX”) and cyclotetramethylenetetranitramine (“HMX”). The burn rate of diamine-dinitro IHE without oxidizer may be similar to RDX without oxidizer. The bum rate of diamine-dinitro IHE without oxidizer may be 8,800 m/s versus 8,930 m/s for RDX without oxidizer. Furthermore, diamine-dinitro IHE may have a lower impact sensitivity and friction sensitivity compared to RDX. The impact sensitivity as measured by with a BAM Impact Tester for diamine-dinitro IHE may be 126-159 cm compared to 38 cm for RDX. The friction sensitivity as measured with using a BAM small-scale friction test may be 168-288 N for diamine-dinitro IHE compared to approximately 120 N for RDX.

The following publicly available table compares sensitivity and performance attributes of diamine-dinitro IHE with RDX.

TABLE 1 Sensitivity and Performance diamine-dinitro Item Attributes IHE RDX 1 Dropweight impact, 2 kg BAM (cm) 126-159 38 2 Friction, BAM (N) 168-288 ~120 3 Electrostatic discharge, no ignition 0.45 0.45 (J) 4 Detonation Pressure (kbar) 340 350 5 Detonation velocity (m/s) 8800 8930 6 Vacuum thermal stability, 100 C., 48 hr <0.1 <0.1 (mL/g)

As shown in the above Table, the first three attributes may be related to safety, with higher values representing greater safety. From this perspective diamine-dinitro IHE clearly may have better attributes with respect to impact and friction. Electrostatic sensitivity may be essentially the same as RDX. Items 4 and 5 may be related to detonation performance, and the values may indicate that diamine-dinitro IHE may be close to RDX in this respect. Item 6 may be related to thermal stability, and the values may indicate that diamine-dinitro IHE may have similar thermal characteristics to RDX.

Diamine-dinitro IHE may be provided in a variety of particle sizes as desired for a particular application. Without limitation, diamine-dinitro IHE may have a particle size from about 1 micron to about 500 microns, for example, from about 20 microns to about 40 microns, from about 50 microns to about 100 microns, about 100 microns to about 200 microns, or about 250 microns to about 300 microns. One of ordinary skill in the art should be able to select an appropriate particle size for the diamine-dinitro IHE for a particular application.

FIG. 1 illustrates an example of a downhole perforating system 10 operating from a platform 12. Platform 12 may be centered over a subterranean formation 14 located below the surface 16. A conduit 18 may extend from deck 20 of platform 12 to wellhead installation 22 including blow-out preventers 24. Platform 12 may have a hoisting apparatus 26 and a derrick 28 for raising and lowering pipe strings, such as, for example, work string 30 which may comprise the downhole perforating system 10. As illustrated, the downhole perforating system 10 may be disposed on a distal end of work string 30. It should be noted that while FIG. 1 generally depicts a subsea operation, those skilled in the art will readily recognize that the principles described herein are equally applicable to land-based systems, without departing from the scope of the disclosure.

Wellbore 32 may extend through the various earth strata including subterranean formation 14. While downhole perforating system 10 is disposed in a horizontal section of wellbore 32, wellbore 32 may include horizontal, vertical, slanted, curved, and other types of wellbore geometries and orientations, as will be appreciated by those of ordinary skill in the art. A casing 34 may be cemented within wellbore 32 by cement 36. When it is desired to perforate subterranean formation 14, the downhole perforating system 10 may be lowered through casing 34 until the downhole perforating system 10 is properly positioned relative to subterranean formation 14. The downhole perforating system 10 may be attached to and lowered via work string 30, which may include a tubing string, wireline, slick line, coil tubing or other conveyance. Thereafter, shaped charges 50 within downhole perforating system 10 may be sequentially fired. As will be discussed in more detail below, an explosive component contained in the downhole perforating system 10 may comprise diamine-dinitro IHE. Upon detonation, shaped charges 50 may form jets that may create a spaced series of perforations extending outwardly through casing 34, cement 36 and into subterranean formation 14, thereby allowing formation communication between subterranean formation 14 and wellbore 32.

FIG. 2 illustrates an example of a downhole perforating system 10. Downhole perforating system 10 may comprise a firing head subassembly 38, a handling subassembly 40, and a gun subassembly 44. Alternatively, downhole perforating system 10 may include a plurality of gun subassemblies 44 (e.g., as shown in FIG. 1). As illustrated, firing head subassembly 38 may be disposed at an upper end of downhole perforating system 10. Handling subassembly 40 may be disposed between gun subassembly 44 and firing head subassembly 38. Handling subassembly 40 may be coupled to firing head subassembly 38 and gun subassembly 44 by any suitable means, such as, for example, mechanical fasteners, welds and/or threads. Firing head subassembly 38 may include ignition device 68. As illustrated, ignition device 68 may be disposed within at least a portion of firing head subassembly 38. Firing head subassembly 38 may include detonating cord initiator 52, detonating cord 54 and donor booster 56 (bi-directional booster). Detonating cord 54 may extend from detonating cord initiator 52 to gun subassembly 44. Handling subassembly 40 may include acceptor booster 70 (bi-directional booster) coupled to detonating cord 54. Detonating cord 54 may be discontinuous between donor booster 56 and acceptor booster 70. There may be air gap 72 between donor booster 56 and acceptor booster 70. Donor booster 56 and acceptor booster 70 may comprise compressed particles of an explosive component. Without limitation, the explosive component may comprise any suitable explosive component, including, without limitation, diamine-dinitro IHE, or another insensitive high explosive component such as triaminotrinitrobenzene (“TATB”). The donor booster 56 may be capable of transmitting a detonation across a discontinuity such as an air gap 72. It does this by its own detonation, in response to a detonation of an adjacent secondary high explosive mass (e.g., detonating cord 54), the donor booster 56 detonation yielding a sufficiently high output to enable transmission across the air gap 72 or the like. Because of the output requirements, a donor booster 56 may comprise a secondary high explosive; such secondary boosters may not continue/allow a detonation over any discontinuity, for example, an air gap 72. This may mean that the donor booster 56 and the detonating cord 54 to which it is coupled may be in direct physical contact.

An acceptor booster 70, on the other hand, may be one which may detonate in response to another detonation, i.e., in response to the detonation of a donor booster 56 which may be spaced from the acceptor booster 70 by a discontinuity such as an air gap 72; the acceptor booster 70 may further be capable of detonating another secondary high explosive mass (e.g., detonating cord 54) in operative association with it by means of the acceptor booster 70's own detonation. Thus, an acceptor booster 70 may continue/allow a detonation from a donor booster 56, even across a discontinuity, and may transmit the detonation to another secondary high explosive mass so as to continue/allow the detonation. Therefore, to continue/allow the detonation, it may be essential that an acceptor booster 70 detonate, and not deflagrate.

Ignition device 68 may be coupled to detonating cord initiator 52 and may provide a substantial amount of the energy to ignite detonating cord initiator 52. A signal (e.g., electrical, mechanical, etc.) may be sent form the surface 16 (e.g., shown on FIG. 1) to activate ignition device 68, which may in turn ignite detonating cord initiator 52. Ignition device 68, may include, but is not limited to, a rig environment detonator igniter, industry standard resistor detonators, hotwire igniters, exploding bridgewire igniters, exploding foil initiator igniters, conductive mix igniters, percussion actuated igniters, and a high tension igniting system. Detonating cord initiator 52 may comprise compressed particles of an explosive component. Without limitation, the explosive component in detonating cord initiator 52 may comprise any suitable explosive component, including, without limitation, diamine-dinitro IHE or another insensitive high explosive component such as TATB.

With continued reference to FIG. 2, gun subassembly 44 may be coupled to detonating cord 54. Gun subassembly 44 may include shaped charges 50. Ignition of detonating cord 54 by ignition device 68 may set off a shock wave that ignites shaped charges 50. Detonating cord 54 may comprise compressed particles of an explosive component. Without limitation, the explosive component in detonating cord 54 may comprise any suitable explosive component, including, without limitation, diamine-dinitro IHE, and TATB. By way of example, the explosive component in detonating cord 54 may comprise diamine-dinitro IHE, such as superfine diamine-dinitro IHE powder. Diamine-dinitro IHE powder having a particle size of from about 1 to about 15 microns may be considered superfine.

Gun subassembly 44 may comprise gun body 74. As illustrated, gun body 74 may be in the form of a cylindrical sleeve. Gun body 74 may comprise a plurality of charge holding recesses 48 which hold shaped charges 50. Each of shaped charges 50 may comprise diamine-dinitro IHE. The plurality of shaped charges 50 may be arranged in a spiral pattern such that each of the shaped charges 50 may be disposed on its own level or height and may be individually detonated so that only one shaped charge 50 may be fired at a time. Alternate arrangements of the plurality of shaped charges 50 may be used, including cluster type designs wherein more than one shaped charge 50 may be at a same level and may be detonated at the same time. Upon ignition, shaped charges 50 may generate a jet that may penetrate casing 34, cement 36 and into subterranean formation 14, which are shown on FIG. 1, for example.

FIG. 3 is a schematic illustration of detonating cord initiator 52 coupled to detonating cord 54. Detonating cord initiator 52 may include booster sleeve 66 which may include an explosive component. Detonating cord initiator 52 may fire the shaped charges 50 (e.g. shown on FIGS. 1, 2, and 5), via detonating cord 54, donor booster 56 (e.g. shown on FIG. 2) and acceptor booster 70 (e.g. shown on FIG. 2), after detecting an appropriate command from the surface 16 (e.g. shown on FIG. 1). Ignition device 68 (e.g. shown on FIG. 2 may be used to activate detonating cord initiator 52. The explosive component of detonating cord initiator 52 may include a first booster stage 60 and a second booster stage 58. The second booster stage 58 may be the subsequent detonation after the detonation of the first booster stage 60. Second booster stage 58 and first booster stage 60 may utilize any suitable explosive component, including diamine-dinitro IHE. Without limitation, first booster stage 60 may comprise superfine diamine-dinitro IHE powder to detonate the diamine-dinitro IHE bulk crystals that may be used in second booster stage 58. Diamine-dinitro IHE particles having a particle size of from about 50 to about 500 microns may be considered bulk crystals.

FIG. 4 is a schematic illustration of bi-directional boosters: donor booster 56 and acceptor booster 70. These two boosters may have identical configurations. Donor booster 56 and acceptor booster 70 may be disposed in booster sleeve 66. Each donor booster 56 or acceptor booster 70 may include a stage 1 detonation which may include a first booster stage 60 and a second booster stage 58. First booster stage 60 and second booster stage 58 may utilize any suitable explosive component, including diamine-dinitro IHE. Without limitation, first booster stage 60 may comprise superfine diamine-dinitro IHE powder to detonate diamine-dinitro IHE bulk crystals that may be used in second booster stage 58. Diamine-dinitro IHE particles having a particle size of from 1 to about 15 microns may be considered superfine.

FIG. 5 illustrates a shaped charge 50. Each of shaped charges 50 may include a booster charge 62 which may include any suitable explosive component, including without limitation, diamine-dinitro IHE. By way of example, booster charge 62 may comprise superfine diamine-dinitro IHE powder. Additionally, each shaped charge 50 may include a main charge 64 which may include any suitable explosive component, including without limitation, diamine-dinitro IHE. By way of example, main charge 64 may comprise diamine-dinitro IHE bulk crystals. The main charge 64 may be used with or without a binder. Booster charge 62 may function as an igniter to ignite main charge 64. Each of the shaped charges 50 may further include an outer housing 76 and a liner 78. As illustrated, liner 78 may generally be in the form of a conical liner. Main charge 64 may be disposed between each outer housing 76 and liner 78. Liner 78 may hold main charge 64 in place. Upon ignition ofthe shaped charge 50, liner 78 may generate a jet that may penetrate casing 34, cement 36 and into subterranean formation 14, which are shown on FIG. 1, for example.

Without limitation, a downhole perforating system may comprise a firing head subassembly; a gun subassembly; and an explosive component comprising 1,1-diamino 2,2-dinitroethylene. The downhole perforating system may comprise any of the following elements in any combination. The firing head subassembly may comprise a detonating cord initiator, wherein the detonating cord initiator comprises the explosive component. The downhole perforating system may further comprise bi-directional boosters comprising the explosive component. The downhole perforating system may further comprise a detonating cord comprising the explosive component. The downhole perforating system may further comprise a plurality of shaped charges arranged in a cluster. The downhole perforating system may further comprise a plurality of shaped charges arranged in a spiral. The 1,1-diamino 2,2-dinitroethylene may comprise 1,1-diamino 2,2-dinitroethylene bulk crystals. The 1,1-diamino 2,2-dinitroethylene may comprise 1,1-diamino 2,2-dinitroethylene superfine powder. The downhole perforating system may further comprise a handling subassembly. The handling subassembly may be positioned between the firing head subassembly and the gun subassembly.

Without limitation, a downhole perforating system may comprise a detonating cord initiator, a detonating cord coupled to the detonating cord initiator, a plurality of perforating gun subassemblies coupled to the detonating cord initiator, wherein the plurality of perforating gun assemblies may comprise a plurality of shaped charges, wherein the plurality of shaped charges may comprise 1,1-diamino 2,2-dinitroethylene. The downhole perforating system may comprise any of the following elements in any combination. The detonating cord initiator may comprise 1,1-diamino 2,2-dinitroethylene bulk crystals and 1,1-diamino 2,2-dinitroethylene superfine powder. The downhole perforating system may further comprise a donor booster comprising 1,1-diamino 2,2-dinitroethylene bulk crystals and 1,1-diamino 2,2-dinitroethylene superfine powder. The downhole perforating system may further comprise an acceptor booster comprising 1,1-diamino 2,2-dinitroethylene bulk crystals and 1,1-diamino 2,2-dinitroethylene superfine powder.

Without limitation, a method may comprise lowering a downhole perforating system into a casing of a wellbore, wherein the downhole perforating system may comprise 1,1-diamino 2,2-dinitroethylene; detonating the 1,1-diamino 2,2-dinitroethylene; and perforating the casing. The method may comprise any of the following elements in any combination. The detonating may comprise sequential detonation of a plurality of shaped charges, wherein the plurality of shaped charges may comprise the 1,1-diamino 2,2-dinitroethylene. The detonating may comprise simultaneous detonation of a plurality of shaped charges. The plurality of shaped charges may comprise a booster charge and a main charge. The main charge may comprise 1,1-diamino 2,2-dinitroethylene bulk crystals. The method may further comprise allowing formation communication between a formation and the wellbore.

The preceding description provides various examples of the systems and methods of use disclosed herein which may contain different method steps and alternative combinations of components. It should be understood that, although individual examples may be discussed herein, the present disclosure covers all combinations of the disclosed examples, including, without limitation, the different component combinations, method step combinations, and properties of the system. It should be understood that the compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of or “consist of” the various components and steps. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces.

For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited.

Therefore, the present examples are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular examples disclosed above are illustrative only, and may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual examples are discussed, the disclosure covers all combinations of all of the examples. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. It is therefore evident that the particular illustrative examples disclosed above may be altered or modified and all such variations are considered within the scope and spirit of those examples. If there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted. 

What is claimed is:
 1. A downhole perforating system comprising: a firing head subassembly; a gun subassembly; and an explosive component comprising 1,1-diamino 2,2-dinitroethylene.
 2. The downhole perforating system of claim 1, wherein the firing head subassembly comprises a detonating cord initiator, wherein the detonating cord initiator comprises the explosive component.
 3. The downhole perforating system of claim 1 further comprising bi-directional boosters comprising the explosive component.
 4. The downhole perforating system of claim 1 further comprising a detonating cord comprising the explosive component.
 5. The downhole perforating system of claim 1 further comprising a plurality of shaped charges arranged in a cluster.
 6. The downhole perforating system of claim 1 further comprising a plurality of shaped charges arranged in a spiral.
 7. The downhole perforating system of claim 1, wherein the 1,1-diamino 2,2-dinitroethylene comprises 1,1-diamino 2,2-dinitroethylene bulk crystals.
 8. The downhole perforating system of claim 1, wherein the 1,1-diamino 2,2-dinitroethylene comprises 1,1-diamino 2,2-dinitroethylene superfine powder.
 9. The downhole perforating system of claim 1 further comprising a handling subassembly.
 10. The downhole perforating system of claim 9, wherein the handling subassembly is positioned between the firing head subassembly and the gun subassembly.
 11. A downhole perforating system comprising: a detonating cord initiator; a detonating cord coupled to the detonating cord initiator; and a plurality of perforating gun subassemblies coupled to the detonating cord, wherein the plurality of perforating gun assemblies comprises a plurality of shaped charges, wherein the plurality of shaped charges comprises 1,1-diamino 2,2-dinitroethylene.
 12. The downhole perforating system of claim 11, wherein the detonating cord initiator comprises 1,1-diamino 2,2-dinitroethylene bulk crystals and 1,1-diamino 2,2-dinitroethylene superfine powder.
 13. The downhole perforating system of claim 11 further comprising a donor booster comprising 1,1-diamino 2,2-dinitroethylene bulk crystals and 1,1-diamino 2,2-dinitroethylene superfine powder.
 14. The downhole perforating system of claim 11 further comprising an acceptor booster comprising 1,1-diamino 2,2-dinitroethylene bulk crystals and 1,1-diamino 2,2-dinitroethylene superfine powder.
 15. A method comprising: lowering a downhole perforating system into a casing of a wellbore, wherein the downhole perforating system comprises 1,1-diamino 2,2-dinitroethylene; detonating the 1,1-diamino 2,2-dinitroethylene; and perforating the casing.
 16. The method of claim 15, wherein the detonating comprises sequential detonation of a plurality of shaped charges, wherein the plurality of shaped charges comprises the 1,1-diamino 2,2-dinitroethylene.
 17. The method of claim 16, wherein the plurality of shaped charges comprises a booster charge and a main charge.
 18. The method of claim 17, wherein the main charge comprises 1,1-diamino 2,2-dinitroethylene bulk crystals.
 19. The method of claim 15, wherein the detonating comprises simultaneous detonation of a plurality of shaped charges.
 20. The method of claim 15 further comprising allowing formation communication between a formation and the wellbore. 